Let me say that I believe there needs to be an approach for boosters based on actual antibody tests of individuals. While there is strong evidence the immunocompromised and elderly (above 65) will need boosters earlier than the one year mark -- many other people may not require boosters before one year if they have sufficient antibody levels from their original vaccinations.
It would be best to test every individual at the eight month mark and later intervals as well to see if they have sufficient Covid antibody levels to stop infection. Only give boosters to those whose antibody levels are low (below a threshold).
There are now
cheaper antibody tests available (and under development) which can quickly provide Covid antibody results. They should ask people to take a antibody test before they get a booster shot... and tell them when they need to come back for their next test in several months (if more vaccination is not needed).
Of course there is the question of who would pay for these antibody tests -- there would need to be government funding to support this testing. I would note the overall cost nationwide in the U.S. would be a tiny fraction of what the government has spent on Covid.
Likewise this approach can be used for allowing "natural immunity" after infection count as a vaccination for "passport" purposes. It should be noted that governments in Europe only allow "natural immunity" post-Covid infection to count for 90 days. In some individual the antibody levels may be sufficient for many months after this mark, and in others not last after this mark. As noted before, studies have shown
40% of individuals infected with Covid do not have sufficient antibody levels to stop reinfection at the 6 month mark -- however this means that 60% do have sufficient levels to stop reinfection at the six month mark and beyond.
IMO those wanting "natural immunity" should be tested every three months after recovery and considered to be the equivalent of vaccinated for "passport" purposes if their Covid antibody levels are above the threshold to stop re-infection. However if an individual who was naturally infected with Covid does not have sufficient antibody levels then they would be required to get a booster vaccination.
I will note there have been a few medical professionals in Europe who pushed for this type of antibody testing of the infected to allow "natural immunity" to be counted for longer than 90 days.
I recognize this type of policy supporting testing for "natural immunity" would be controversial when the national focus is to get everyone vaccinated -- and they even have mandated large employers with 100 employees in the U.S. require vaccination. Along with the reality that the associated risk from catching Covid with a Case Fatality Rate of 2% is a terrible way to obtain immunity.
Coupled with concerns along the lines of what if you have "natural immunity" at 6 months and then not at 9 months -- during this three month interval is the person an infection risk vector. Well -- the reality is that the vaccinated needing boosters have the same type of risk.
Effectively the first-generation of Covid vaccines, which are not universal or permanent, have the same types of risk with fading immunity that "natural infection" has. No matter which path an individual acquired immunity from -- vaccination or natural infection -- their immunity is going to fade over time. The question is how quickly. And the best way to create a national strategy to prevent re-infections and spread is to tailor antibody testing to individuals.